Back when record singles would carry both an A and B side, the Notorious B.I.G. took that opportunity to show off the range of his rap talent. With 1994's "Juicy," the first single off of his classic debut Ready to Die, the Brooklyn lyricist also offered another track — maybe not as catchy, but equally as captivating. If you ask B.I.G.'s friend and producer DJ Clark Kent, that track is among Biggie's greatest songs.

Produced by the highly regarded DJ Premier, "Unbelievable" mixed a thumping track and raw lyrics with an unlikely R&B sample for some head-nodding results. Back in 1994, there was still a stigma attached to mixing R&B with hard-core hip-hop, and even DJ Premier once admitted that he thought it would be a bad idea to use R. Kelly's vocals from "Your Body's Calling" for the underground song's hook. Premier initially argued that the sample wouldn't match beat he'd chopped up from the Honey Drippers' 1973 classic "Impeach the President." But in the end, it all blended perfectly.

"The record, it's so hard, the rhymes were so hard and the beat was so hard," DJ Clark Kent told Sway. "And he took R. Kelly's singing and made it a hook. How do you take something that pretty, put it on a beat that hard and then rhyme crazy and it comes out that perfect?"

To honor the [article id="1680779"]late Notorious B.I.G.[/article], who was murdered 15 years ago on March 9, his protégé Lil' Cease and DJ Clark Kent, who produced classics like Jay-Z and Biggie's "Brooklyn's Finest" as well as Junior M.A.F.I.A.'s "Player's Anthem," sat down with MTV News correspondent Sway Calloway to talk about their [article id="1680993"]all-time favorite B.I.G. tracks[/article].

From the song's opening bars, Big planted his King of New York flag, spitting, "Live from Bedford-Stuyvesant, the livest one, representing BK to the fullest."

Later in song, Big would cleverly take a jab at rapper Kwamé's short-lived polka-dot fashion craze, ponder the age-old boxers-versus-briefs debate and proclaim himself as "the illest."

"The rhymes were out of this world, and I think the records that I love the most from Big are the records with the best rhymes, and those rhymes were just out of this world," Clark said.

Join MTV News as we celebrate the Notorious B.I.G's life on the 15th anniversary of his death. From now through March 25, we will be rolling out exclusive and commemorative content from Biggie's closest friends, collaborators and his biggest fans. To join the conversation on Twitter, hit @MTVRapFix using the hashtag #biggie15.